Compressor



P. ANDERSSON COMPRESSOR Filed May 10, 1926 March 19, 1929.

Patented Mar. 19, 1 -92 9.

- UNITED, STATES DELAWARE.

Application filed Mayd This invention relates generally to new i and useful improvements in the construction tion'is to provide a new and useful unload ing device especially applicable to air or gas compressors. These and other objects and advantages will be apparent from the following, description. I

Some of the novel features of valve structure disclosed but not specifically claimed herein, .form' the subject. of a divisional application filed January 18, 1929 'A clear conception of several embodiments of the novel features and'oftheoperation of devices embodying the invention, may be hadby referring to the'drawingaccompany-- ing and forming a partof this specification in which like reference characters designate views.

one ofthe inlet valves;

the same I Fig. 1 is a somewhat diagrammatic and part sectional'side elevation of a compressor cylinder, the section being taken adjacent to- Fig. 2 is an" enlarged sectional view of one of the compressor inlet valves showing the unloading mechanism associated therewith.

and exhaust valves communicating with the Fig. 8 is an'enlarged sectional vi'ew of one ofthe compressorinlet valves having a modified form of unloading" mechanism associated therewith. w

The compressor to-"which the inventionhas been specifically applied herein, is of the constant speed typeand comprises a cylinder 2 having therein a usual form. of reciprocable piston, andalso having end heads 3, 4 within which are located inlet l air supply anddischarge conduits 36, 37 respectively. The compressor pistonmay be reciprocated in any convenient manner, as by an electric motor, and the pressure of the compressed air delivered through the discharge conduits 37' varies according to positioning cam 14:.

or similar parts in the various .PELLE ANDERSSON, 0F MILWAUKEE, Wisconsin, Assreuon To ALLrs-oHALMnas- MANUFACTURING COMPANY, or Mrmvanxns, WISCONSIN, A, CORPORATION or comrn'n-sson.

1926. Serial no. 107,907.

the demand for air at the source-of utili'za tion. T j r The improved inlet valve structure shown" in Figs 2 and3, comprises an annular sheet metal or plate valve 18 which is constantly urged toward an, annular seating 241 formed on the seating element 20, by means of one or more springs 19 which react against a valve s'top'17. The valve stop 17 is rigidly secured to the seating element 20'by means of a clamping bolt, 21', and has a recess", formed to receive the valve 18 when in open position, so that thedisoharge edge of the valve '18 is completely surrounded by an annular lip 23 when the valve is fully open.

The"improvedunloading device shown in Fig. 2, comprises a bridge piece or member 16 movably supported from the seatingele- I ment '20 by means of parallel links 15, 25, and is disposed between the valve 18 and a The links 15, 25 are mounted to swing about upper fixed pivots andhave" their lower ends pivotally associated with lower pivots secured to the bridgemember 16, thereby causing the contact surface of the member 16 to always as sume parallel positions. The bridge mentb'er'lri carries a roller 35 which is held in en'- gagement with one ofthe surfaces 38, 39, 40

. of the cam 14: by means of a spring 22 which reacts against the seating element 20. The

card li is supported upon a cam shaft 11 and ondarcuate bridge releasing surface39 of shorter radius than that of the surface 38, and an intermediate surtace 4L0 connecting the surfaces38, 39, all of the surfaces 38, 39, 40 being adapted to engage the roller-35- at certain times. The cam shaft 11 is angularly adjustable and oscillatable duringoperation'of the compressor, by means of arocker arm 13 and a connection 9, in a manner to be later explained.

' Thew modified unloading device shown hasanarcuateunloading surface 38, a "se(:-

in Fig. comprises a bridge piece or mem- 7 her 26 m'ovably suspended from the cyl inderl1e'ad4and from an extensionon the seating element 20, by means of an arm27 formed it. with the member 26;- The arm 27 pivotally supported at its upper end "and carries a roller. 35 at'it s lower extremity, which' cooperateswith the surfaces 38, '39, 40 of-the' adjacent (321111 1 1.

1 Fig.

The

remainder of the unloading device of Fig.

3 is substantially similar to that of 2, both in structure and mode of operation,'but the contact surface of the member .26 does-not move to parallel positions.

The actuating mechanism for the unloading devices, comprises a regulator '5 mounted laterally adjacent to the cylinder 2 and consisting of an auxiliary cylinder having therein a vertically movable plunger 29. A pipe 28 provides a connection from the discharge conduit 37 or other pressure source,to the oil chamber within the regulator casing, and this oil chamber communicates with the plunger chamber past a needle valve 41. The plunger rod 30 is adapted to transmit motion to levers 31 which are in turn adapted to adjust the T-lever 7 about its supporting pivot 33, through a connection The supporting pivot 33 of the T-lever 7 is associated with the lower swinging end of the oscillatory lever 6 the upper end of which is supported by a fixed pivot 42. The lever 6 is swingable back and forth during normal operation of the compressor, by means of a con nection 3i, and the upper and lower arms of the T-lever 7 are joined to the rocker arms 12, 13 by means of connections 8, 9 respectively. Asi previously explained, the rocker armsv 12, 13 are secured to the cam shafts 10, 11 carrying the unloading cams 14.

During normal operation of the compressor, the piston is being reciprocated to alternately draw air into and discharge air from the opposite ends of the cylinder 2 through the inlet and discharge conduits The connection 34: is being reciprocated. simultaneously with the reciprocation of the piston, thus producing oscillation. of the lever 6 about the pivot 42 and causing the T-lever 7 to rock with the lever 6. I The rocking motion of the T-lever 7 is transmitted through the connections 8, 9: and the arms 12, 13 to the cam shafts '10-, 11 thus producing periodic rocking movement of the cams 14. When the cam 14 is in the position shown in Fig. 2 with the cam surface 38 engaging the roller 35 of the adjacent bridge member, throughout the rocking movement, the bridge member holds the inlet-valve 18 in open position throughout the compression .stroke and the compressor is fully unloaded. When the cam 14 is in the position shown in Fig. 3 with the cam surface 39 in engagement with the roller 35 of the bridge member, throughout the rocking'movement, the bridge member does not engage the inlet valve.18 and this valve functions normally to admit air to the cylinder on the suction stroke and to prevent escape of air past the valve on the return stroke.

By proper adjustment of the position of the cams 14, unloading may obviously be effected during any desired portion of the compression stroke. Such'adjustment of the cams 1 1- may be automatically accomplished in accordance with variations in the discharge pressure or of any other variable operating characteristic, bynieans of the regulator 5; As-the pressure admitted through the pipe 28 increases, the plunger 29and rod 30 move upwardly thereby causing the cam surfaces 38 to become effective the unload- The lip 23 surrounding thevalve 18 prevents the air which returns to the inlet conduit 36 during unload ng, from returning the valve to its seating 24 thereby ,pro-

ducing highly efficient unloading. The an H nular sheetmetal or plate valves 18 are of simple construction and have proven highly efficient in operation. T 1

It should be understood that it is not desired to limit the invention. claimed to the exact details of construction shown anddescribed, for obvious modifications may occur to persons skilled in the art. 7

n in Figs. 1

It is claimed and desired to secure by Iiet ters Patent: Y

1. In a. compressor, a cylinder, an inlet valve for controlling admission of air to said'cyli'nder, means for constantly urging said valve toward closed position,'amember adapted to hold said valve in open position, a camfor adjustably positioning said memher, and means for continuously rocking said cam during operation ofthe compressor.

2. In a compressor, a cylinder, an annular sheet metal inlet valve for controlling ad mission ofair to said cylinder, spring means for constantly urging said valve toward closed position, abridge member adapted to prevent said valve from seating, a cam for adjustably positioning said member, and means for continuously rocking said cam during operationof the compressor.

3. In a compressor, a cylinder, an inlet valve for controlling admission of air to said cylinder, means for constantly urging said valve toward closed position, a member adapted to hold said valve in open position,

ber, means for varying the position of said cam 1n. accordance with variations in the a cam for adjustably positioning said memdischarge pressure,- and means for rocking said cam during operation of the compressor. 4. In a compressor, a cylinder, an annular sheet metal inlet valve for controlling admission of air to said cylinder, spring means for constantly urging said valve toward closed position, a bridge member adapted to prevent said valve' from seating, a cam for adjust-ably positioning said member, means for varying the position of said cam in accordance with variations in the discharge pressure, and means for rockingsaid cam during operation of the compressor. 5. In a compressor, a cylinder, an inle valve for controlling admission of air to said cylinder, means for constantly urging said valve'toward closed position, a member adapted to hold said valve in open position,

a cam for adjustably positioning sald mem-. ber, means or adjusting said cam in accordance with variations in the discharge 'ressure, and means or continuously roc ing said cam during operation of the compressor. r

6. In a compressor, a cylinder, an annular sheet metal inlet valve for controlling adm1ss1on of alr to said cylinder, spring means for constantly urging said valve toward closed position, a bridge memberadapted to hold said valve in open position, a roller carried by said bridge member, a cam coacting with said roller for adjustably positioning said member, means for adjusting the position of said cam in accordance with variations in the discharge pressure, and means for rocking said cam during operationof the compressor.

7 In a compressor, a cylinder, an annular sheet metal inlet valve for controlling admission of air to said cylinder, spring means 40 for constantly urging said valve toward closed position, a bridge member adapted to hold'said valve in open position, a roller carried by said bridge member, a cam coacting With said roller to hold said valve in open position, spring means for urging said member toward said cam, means foradjust- .ing the position ofsaid cam in accordance 'Wlth variations in the discharge pressure,

and means for rocking said cam during operation of the compressor.

In testimony whereof, the signature'of the inventor is afiixed hereto.

PELLE ANDERSSON; 

